When should I move on from doing Overhead Squats, and start learning the Snatch progressions (Tall Muscle Snatch, Scarecrow Snatch, etc.)?

I am male, 5’11’’ tall, weighing 200lbs and 30 years old. I have worked out several times a week for the past 10 years, doing typical body building/strength training workouts. However, having gotten bored doing these types of workouts and wanting to include Olympic Weightlifting as a big component of my weekly workouts. Last summer I sold off most of my existing workout equipment and bought a bar and some bumper plates, a book and instructional DVD, and got to work. Over the course of 3 months I got up to being able to Clean 175lbs for 1 rep. However, my technique was very poor (early arm bend, feet transitioning at the wrong time, etc.). I therefore, did some research and discovered Greg Everett’s book and DVD and ever since it has been my bible. I ditched the learning progression I had been following and instead followed what Greg recommended, which was learning the Snatch first (instead of the Clean). It quickly became apparent that having never done any Overhead Squats, I did not possess the required flexibility to do this movement. And spent the next few months doing only Overhead Squats*, and am now able to Overhead Squat 148lbs for 1 rep and 121lbs for several reps.

As Greg states the Overhead Squat should be sound before doing the Snatch, is the weight I can currently Overhead Squat sufficient to start learning the Snatch, or should I continue to only train the Overhead Squat until I can lift more weight?